铸态(TiB+TiC)/Ti1100 复合材料高温拉伸性能及蠕变行为

The as-cast microstructure, high temperature tensile properties and creep behaviors of (TiB+TiC)/ Ti1100 composite were characterized in detail by XRD, SEM and TEM. The results show that the composite possesses a typical basket-weave structure. TiB and TiC are formed in situ through the reaction of B₄C, C and Ti. With the increase of temperature, the ultimate tensile strength decreases from 766 MPa to 511 MPa. In the test range, the steady creep rates of (TiB+TiC)/Ti1100 composite decrease with the increase of temperature and stress. According to the calculation of relevant data, the stress exponent and activation energy of the composite are 3.75 and 269.5 kJ/mol, respectively. Combined with the microstructure after creep deformation, it can be determined that the creep process is mainly controlled by dislocation slip. The α/β interfaces are the main obstacle of dislocation slip, while TiB, TiC and silicides also hinder the movement of dislocations. A large degree of β-Ti dissolution leads to the formation of fine silicide and reduces the blocking effect of α/β interface on dislocation. The reinforcements, especially TiB, can improve the stress concentration in matrix through the bearing effect and thus inhibit the β-Ti dissolution.